1. Field of the Invention
This invention relates to drill pipes, shafts or rods used to bore holes in the earth and wire wound flexible hollow rods.
2. Prior Art
There have been attempts to develop a hollow flexible drill pipe before and wire wound flexible hollow pipes have been experimented with but failed because the hollow center collapsed when the pipe was put under the high torsion loads required in a drilling operation. This happens because the spring wire required to make a flexible hollow pipe is bendable and a pipe made of spring wire needs a core in which the spring wire will not bend or collapse through. A flexible pipe used to drill holes in the earth requires a hollow center so drilling fluids can be pumped through the pipe to remove drilling cuttings from the hole being drilled. There has been a long recognized need in the petroleum and mining industries for a small flexible drill pipe that can drill small angle holes or curved holes from a large diameter well or bore hole.